Looms for weaving

ABSTRACT

In order to ensure that such various loom operations as dobbyshedding and box-changing occur at a requisite stage in a loom cycle of operation, even on restarting after a loom stoppage, a speed sensitive switch driven from a loom shaft is provided in the circuit to the drive motor of each respective auxiliary so as to ensure that the auxiliaries are not energized until the loom shaft has attained a predetermined rotational speed.

United States Patent Hindle et al.

[451 Aug. 1,1972

[54] LOOMS FOR WEAVING [72] Inventors: Thomas Hindle; Vincent Pinder Banks, both of Blackburn, England [73] Assignee: Hindle, Son and Company Limited,

Blackburn, England 22 Filed: Feb. 26, 1970 21 Appl.No.: 14,552

[30] Foreign Application Priority Data Feb. 26, 1969 Great Britain ..10,l59/69 [52] US. Cl. ..139/76, 139/1 E [51] Int. Cl. ..D03d 51/20 [58] Field of Search ..139/55, 57, 66, 1, 76, l E

[56] References Cited UNITED STATES PATENTS 2,787,290 4/1957 Rapp et al. ..l39/l E 3,192,957 7/1965 ONeill ..139/66 FOREIGN PATENTS OR APPLICATIONS 1,801,502 10/1968 Great Britain ..139/76 Primary Examiner-Henry S. Jaudon Attorney-Roberts, Cushman & Grover [5 7] ABSTRACT In order to ensure that such various loom operations as dobby-shedding and box-changing occur at a requisite stage in a loom cycle of .operation, even on restarting after a loom stoppage, a speed sensitive switch driven from a loom shaft is provided in the circuit to the drive motor of each respective auxiliary so as to ensure that the auxiliaries are not energized until the loom shaft has attained a predetermined rotational speed.

4 Claims, 4 Drawing Figures LOOMS FOR WEAVING This invention relates to looms for weaving and more particularly to the control of dobbies and box-motions which are powered by electric motors separately from the main electric motor employed to drive the loom.

In our US. Pat. No. 3,568,725 we have described an electric dobby-shedding motion wherein each healdshaft is actuated by its own electric motor, the dobbyshedding motion comprising a number of such motors, each provided with an automatic brake, which run intermittently for a fraction of the time occupied by a loom cycle. The motors next to be energized are selected by a series of two-way pattern switches actuated by a patterning device in combination with a corresponding number of two-way limit-switches actuated by gearwheels which under their own motor-power, rotate a half-revolution at a time and then stop promptly under automatic braking action. Those motors thus selected are then energized by the closure of a cam-actuated timing switch, or switches, at the appropriate time, or times, in the loom cycle for the heaId-change to commence.

The motors so selected and energized are normally stopped by their limit-switches opening upon their respective gearwheels completingtheir required halfrevolution, whereby the desired positional change of heaId-shaft or shuttle-box is thenceforward efiected by means of cranks or equivalent eccentrics or cams.

The main motor employed to drive the loom (other than its dobby and box-motions) may be started and stopped to start and stop the loom. More usually, however, the main motor runs continuously and drives the loom through some form of friction clutch, such as a conventional electro-magnetic clutch as shown in FIG. 3.

In the process of weaving, the loom may be stopped at any position in the loom cycle, and it is apparent that when the loom is brought to rest either by stopping its motor or by releasing the driving clutch (and usually by the application of supply simultaneously brake) the several independent electric motors employed to power the dobby shedding motion and/or the box-motion must simultaneously be de-energized, and their normal running operations thereby interrupted.

For example, when the loom is stopped by the operator with the slay nearly or fully forward, the healds and boxes then in course of changing their positions will be only about half-way through their changing movements when they are arrested by interruption of their current supply simultaneously with switching-off or declutching the main motor.

Simultaneous stoppage of the loom itself and of the independent electric motors employed to power the dobby and box-motion is readily achieved by normal switching technique, but when the loom is re-started, in the above described circumstances, it has been found that the dobby and box-motion motors start up and attain their maximum speed very quickly indeed, and therefore complete the remainder of their changing movements well before the loom has picked up its normal running speed. Assuming that the beat-up normally occurs with the changing sheds half-way through their changing movements, there will be a variation of the woven fabric if, upon each such re-starting of the loom, the beat-up occurs after the changing sheds have completed, or nearly completed, their change.

The object of this invention therefore is to provide means whereby, after the loom and its electric dobby and/or box-motion have been stopped as above described, and the loom is re-started to re-commence weaving, the electric current serving to energize the independently-driven dobby and/or box-motion is not restored until after the loom itself has substantially attained its normal running speed.

According to this invention, a speed-sensitive switch is driven from any convenient shaft of the loom, such as the crankshaft. This switch is arranged to control the current supply to the dobby or other auxiliary, so ensuring that these auxiliaries are not energized until the loom crankshaft has substantially attained its normal running speed. The employment of this device effectively synchronizes the action of the electric dobby and any other relevant auxiliary with the loom crankshaft during each re-starting operation, and ensures uniform cloth under all running and re-starting conditions.

The invention will now be described further, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a circuit diagram of one form of electric dobby, showing only the components required for actuating one heald-shaft, but including a speed-sensitive switch S in accordance with the invention;

FIG. la diagrammatically illustrates a conventional electromagnetic clutch;

FIG. 2 is a modification of the timing switch for use when the main motor employed to drive the loom crankshaft is adapted to be reversed for the purpose of unweaving faulty cloth;

FIG. 3 is a diagrammatic perspective view, from behind, a loom dobby constructed in accordance with this invention.

Referring to FIG. 1, one form of the electric dobby shedding motion (or head-motion) described in US. Patent 3,568,725, wherein each heald-shaft is actuated by its own electric motor, such as MI, comprises a number of such motors each of which is provided with an automatic brake 2. Each motor drives through speed-reducing gears indicated by gear-box 3 and spurgears 40 and 4b, and runs intermittently for a fraction (about one-half) of the time occupied by one loom cycle or crankshaft revolution.

The motors, such as Ml, next to be energized are first selected by a series of two-way pattern-switches, such as P1 (with contacts 8 and 9), actuated by a stepby-step patterning device indicated at D, in combination with a corresponding number of two-way limitswitches, such as Ll (with contacts 10 and ll), each such limit-switch being actuated by a cam 7 compounded and rotating with the gearwheel 4b, which, under its own motor-power, rotates a half-revolution at a time and then stops promptly under automatic braking action.

Those motors thus selected are then duly energized by a cam-actuated timing-switch T, with contacts 12, at the appropriate time in the loom cycle for the healdchange to commence. Timing-cam 13 which operates the timing-switch T rotates at the speed of the loom crankshaft, and the cam-lobe extends over about 240 of its circumference.

The motor so selected and energized are normally stopped by their respective limit-switches, Ll etc.,

opening circuit upon their gearwheels 4b and earns 7 completing their required half-revolution, whereby the desired positional change of each heald-shaft is thenceforward effected by a crankpin 4c fixed in gearwheel 4b, forcibly displacing, by means of a connecting-link 5, a respective jack-lever 6 into either its up or down position, whereby,-by simple mechanical connections the desired shedding movements of the heald-shafts are obtained in accordance with the patterning device D.

For the particular form of limit-switch cam 7 shown, by way of example, in FIG. 1, the cam-lobes extend over nearly one-half of their circumference, whereby they change-over their two-way limit-switches after each half-revolution.

It will be understood that the items M1, 2, 3, 4a, 4b, 4c, 5, 6, Pl,'Ll and C l (a contactor coil) shown in FIG. 1 are providedfor each heald-shaft to be controlled in accordance with the patterningdevice D, but that the timing-switch T is common to all the dobby motors. A separate timing-switch (not shown) may be employed to energize the electric box-motion motors, if such are moved in themanner disclosed in our U.S. Pat. No. 3,568,725, since the movement of the shuttle-boxes occupies a smaller fraction of the loom cycle than does the changing'movement of the heald-frames.

The main motor, LN, employed to drive the loom (other than, its dobby and box-motions) may be started and stopped tostart and stop the loom crankshaft.

Referring to. FIG. l, closure of the hand-switch 23,

serves to energize a main contactor coil LC, whereupon contacts-20, 21 and 22 close-to start the main motor LM, thereby driving the loom crankshaft. More usually, however, the main motor runs continuously during normal weaving and drives the loom crankshaft through some form of friction clutch, such as the electro-magnetic clutch illustrated in FIG. 3. In such variation, the" clutch is similarly energized by closure of the hand-switch 23,.thereby settingthe loom crank-shaftinto motion. If preferred, push-button control may be readily substituted for the hand-switch 23 in a, manner well-known in the art."

When the main contactor coil LC closes to start the loom, current is made available at contacts l7, l8 and 19 of the contactor which controls the dobby motor M1 and if the contact coil Cl is energized at such time, by reason of the coils circuit being completed through contacts 12 of the timing-switch T, through contact 8 or 9 of the pattern-switchPl, and through contact 10 or 11 of the limit-switch Ll, the respective dobby motor Ml will promptly start-up, and will continue to run until it is stopped by its limit-switch Ll, opening the circuit of coil Cl, upon gearwheel 4c and cam 7 completing their half-revolution.

The arrangement thus far described will operate in accordance with the disclosure of US. Pat. No. 3,587,625.

However, we have found that the heald shaft motors attain their operating speed more quickly than the loom crankshaft when restarted under load and this more rapid build-up can manifest'itself as a cloth fault or give rise to other difficulties'if the restarting occurs at a particularstage in the loom cycle since the timing relationship between the various loom operations will be upset.

' In order to ensure that a proper timing relationship is maintained between the completion of the shed changing (or box changing) operation and the normal loom cycle of operation on re-starting of the loom after a stoppage thereof and in the event that at the instant of stoppage the motors of those heald shafts next to be changed or in the process of being changed were energized, (or the motors of the-box-changing mechanism were in a like condition), we have found it necessary to delay the energization or re-energization of the healdshaft (or box-change) motors and it is with the provision of a means to achieve this end that the present invention is particularly concerned.

Thus, referring again to FIG. 1 we provide a speed sensitive switch S, which switch is driven from any convenient shaft of the loom, such as the crankshaft, connected in series with the timing-switch T, and therefore in series with any number of contactor coils, such as C1, C2, which themselves are connected in parallel.

The speed-sensitive switch S, which may be of any commercially available construction, is thus adapted to control the current supply to the electric dobby, or other auxiliary, so ensuring that these independently powered auxiliaries-are not energized until the loom crankshaft has substantially attained its normal running speed. The contacts of the'switch S close either when rotation commences or at any speed up to the full speed of the loom, as may be found mosteffective. The switch assumes an open circuit condition in the event of a reduction in the rotational speed of the loom crank shift, as during stopping of the loom.

The employment 1 of this device effectively synchronizes the action of the electric dobby, and any other independently driven auxiliary, with the loom crankshaft during each re-startingoperation, and ensures uniform cloth under all running and re-starting conditions.

The speed-sensitive switch S responds automatically 3 to any difference in the torque required to accelerate the crankshaft when starting under the varying load conditions encountered in weaving a range of industrial fabrics.

In allthe foregoing descriptions it has been assumed that the loom crankshaft rotates only in'one direction. In some instances, however, its direction of rotation is temporarily reversed for the purpose of unweaving in order to remedy a weaving fault. In such variation, as shown in FIG. 2, duplicate timing-switches TF and TR, actuated by duplicate timing-cams l3 and 15, are provided. The hand-switch 16 is changed over when reversing the direction of the crankshafts rotation, that is from the forward to the reverse direction. Alternatively, the timing-cam 13, as shown in FIG. 1, may be adapted to actuate a second switch 14 which is selectively put into action by a hand-switch (similar to '16 of FIG. 2) when the loom crankshaft is temporarily reversed. The angular'disposition of the two timingswitches 12 and l4 around the cam depends, as indicated by FIG. 1, upon the angular spread of the camlobe, the essential requirement being that the dobby motors shall be energized at the same point in the crank-shaft revolution, regardless of its direction of rotation.

In a modification of the electric dobby described in US. Pat. No. 3,568,725, the heald-shafts are actuated by one or more electric motors which run continuously but independently of the main loom motor. Electric clutches are employed to transmit power therefrom for the purpose of rotating a series of crankwheels or cams, each of which actuates one heald-shaft. These crankwheels or cams rotate a half-revolution at a time under the combined control of pattern and limitswitches in the manner described in our co-pending Application aforesaid.

As in the case of the independent intermittently running motors therein described, and herein explained in reference to FIG. 1, the electric clutches employed in the above modification are simultaneously controlled by a speed-sensitive switch, with precisely the self-same object and effect.

What we claim is:

1. A loom and main motor for driving the same, said loom having an electric dobby motion for the selective actuation according to a predetermined pattern sequence of at least one electrically driven auxiliary and wherein each such auxiliary is provided with a respective drive means separate from said main electric motor employed to drive the loom and operable under the control of a pattern means and timing switch means, characterized by a speed sensitive switch driven from a loom shaft and adapted to control the current supply to the drive means for the respective auxiliaries thereby selectively to apply a drive to such auxiliaries in accordance with the pattern sequence aforesaid, the speed-sensitive switch serving to ensure that the auxiliaries are not energized until the loom shaft has attained a predetermined running speed.

2. A loom according to claim 1 wherein the drive means of each auxiliary comprises a continuously driven motor and an electromagnetic clutch means for drivingly connecting such motor to the respective auxiliary, the speed-sensitive switch being operable to control the current supply to the clutch means.

3. A loom according to claim 1 wherein an additional timing switch means is provided to control the operation of the drive means of each auxiliary on operation of the loom in a reverse direction, a manually actuable change-over switch being provided for use on loom reversal.

4. A loom according to claim 3 wherein the additional timing switch means comprises a timing switch and a respective timing-cam therefore. 

1. A loom and main motor for driving the same, said loom having an electric dobby motion for the selective actuation according to a predetermined pattern sequence of at least one electrically driven auxiliary and wherein each such auxiliary is provided with a respective drive means separate from said main electric motor employed to drive the loom and operable under the control of a pattern means and timing switch means, characterized by a speed sensitive switch driven from a loom shaft and adapted to control the current supply to the drive means for the respective auxiliaries thereby selectively to apply a drive to such auxiliaries in accordance with the pattern sequence aforesaid, the speed-sensitive switch serving to ensure that the auxiliaries are not energized until the loom shaft has attained a predetermined running speed.
 2. A loom according to claim 1 wherein the drive means of each auxiliary comprises a continuously driven motor and an electromagnetic clutch means fOr drivingly connecting such motor to the respective auxiliary, the speed-sensitive switch being operable to control the current supply to the clutch means.
 3. A loom according to claim 1 wherein an additional timing switch means is provided to control the operation of the drive means of each auxiliary on operation of the loom in a reverse direction, a manually actuable change-over switch being provided for use on loom reversal.
 4. A loom according to claim 3 wherein the additional timing switch means comprises a timing switch and a respective timing-cam therefore. 